I've been chasing this problem for over a week. When I google for sound problems on Fedora, *every* link returned by Google appears visited--ie. I've read them all and tried them all. I've gone through all the emotional stages of loss: anger, denial, grief, depression, etc., but I've turned the corner and am determined to bring my sound back!

Description of my problem:
A fresh install of Fedora 16 on a Dell Optiplex 390. Initially sound worked fine (I'm using headphones) (YouTube videos played as expected). Then I jumped through some hoops to install Spotify and the sound worked fine there, too. Then I I started noticing problems with YouTube--videos wouldn't autoplay, would stop unexpectedly, or the sound would get choppy. And I noticed that the main system volume control did not affect the volume of YouTube videos. Then the sound in Spotify stopped all together, and that's when things spiraled downward. I started reading everything under the sun about sound problems on Fedora and was installing all sorts of pulseaudio utilities, alsa utilities, and editing conf files. I lost track of everything I did, but the end result is....